During the last decade, one of main focuses of hadronic physics has been the
study of the hadronic structure using hard exclusive reactions,
such as Deeply Virtual Compton Scattering (DVCS),
\(\gamma ^{\ast }N \rightarrow \gamma N\) , and hard exclusive meson production (HEMP),
\(\gamma ^{\ast }N \rightarrow M N\) .
These processes have been the subject of intensive theoretical and
experimental investigations [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}, [10]}, [11]}, [12]}, [13]}, [14]}.
In addition, there were investigated ”inverse” hard exclusive reactions
such as
\(\gamma N \rightarrow \gamma ^{\ast }N \rightarrow l^{+}l^{-}N\)  [15]}
and
\(\pi N \rightarrow \gamma ^{\ast }N \rightarrow l^{+}l^{-}N\)  [16]}, and
”\(u\) -channel” reactions such as \(\gamma ^{\ast } \gamma \rightarrow \pi \pi \)  [17]}.
